As you already know, Blustacks 2 has announced and it is amazing! Much better than first version! I know that many of you are already seeking to root it, so I'm going to tell you how to do it.
I tried Framaroot, Towelroot and KingRoot to root Bluestacks 2. Only KingRoot managed to root newest version of Bluestacks correctly.
All you have to do is just to download KingRoot apk from official XDA thread, install it on Bluestacks and run it. KingRoot will do the rest automatically.
P.S. I don't own Bluestacks, nor KingRoot.